Spectrum of congenital and inherited ocular disorders seen in a genetic clinic: Experience of a developing ocular genetic service

Purpose: Hereditary causes are an important etiological category of childhood blindness. This study reports the real?world experience of a developing ocular genetic service. Methods: The study was carried out from Jan 2020 to Dec 2021 jointly by the Pediatric Genetic Clinic and the Department of Ophthalmology of a tertiary care hospital in North?West India. Children presenting to the genetic clinic with congenital or late?onset ocular disorder(s) and any individual (irrespective of age) suffering from an ophthalmic disorder and referred by an ophthalmologist for genetic counseling for himself/herself and/or his/her family member(s) were included. Genetic testing (exome sequencing/panel?based sequencing/chromosomal microarray) was outsourced to third?party laboratories with the cost of the test being borne by the patient. Results: Exactly 8.6% of the registered patients in the genetic clinic had ocular disorders. Maximum number of patients belonged to the category of anterior segment dysgenesis, followed by microphthalmia anophthalmia coloboma spectrum, lens disorders, and inherited retinal disorders in decreasing numbers. The ratio of syndromic ocular to isolated ocular disorders seen was 1.8:1. Genetic testing was accepted by 55.5% of families. The genetic testing was clinically useful for ~35% of the tested cohort, with the opportunity for prenatal diagnosis being the most useful application of genetic testing. Conclusion: Syndromic ocular disorders are seen at a higher frequency compared to isolated ocular disorders in a genetic clinic. Opportunity for prenatal diagnosis is the most useful application of genetic testing in ocular disorders.

Application of CRISPR/Cas9 genome editing technology in hereditary retinal diseases / 中华实验眼科杂志

Several mutant genes for inherited retinal diseases have been identified, but effective treatments are still lacking.The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) system can edit human genomic DNA by nonhomologous end joining or homology-directed repair, offering more possibilities for the treatment of hereditary retinal diseases.CRISPR/Cas9 not only can genetically correct patient-derived induced pluripotent stem cells (iPSCs) to observe their differentiation into retinal cells thereby, thereby exploring the pathogenesis of the disease and implementing cell therapy, but can also be delivered to the body via vectors and directly act on target cells to achieve in vivo gene editing.CRISPR/Cas9 gene editing technology in hereditary retinal diseases has been mainly used in retinitis pigmentosa, hereditary X-linked juvenile retinoschisis, and Leber congenital amaurosis 10, of which the in vitro application of CRISPR/Cas9 for Leber congenital amaurosis 10 has entered the clinical trial stage.In this paper, we reviewed the mechanism and key advances of CRISPR/Cas9 and provided an overview of gene editing in IRDs.

Therapeutic landscape for inherited ocular diseases: Current and emerging therapies

Inherited ocular diseases comprise a heterogeneous group of rare and complex diseases, including inherited retinal diseases (IRDs) and inherited optic neuropathies. Recent success in adeno-associated virus-based gene therapy, voretigene neparvovec (Luxturna®) for RPE65-related IRDs, has heralded rapid evolution in gene therapy platform technologies and strategies, from gene augmentation to RNA editing, as well as gene agnostic approaches such as optogenetics. This review discusses the fundamentals underlying the mode of inheritance, natural history studies and clinical trial outcomes, as well as current and emerging therapies covering gene therapy strategies, cell-based therapies and bionic vision.

Automated Classification of Inherited Retinal Diseases in Optical Coherence Tomography Images Using Few-shot Learning / 生物医学与环境科学（英文）

OBJECTIVE@#To develop a few-shot learning (FSL) approach for classifying optical coherence tomography (OCT) images in patients with inherited retinal disorders (IRDs).@*METHODS@#In this study, an FSL model based on a student-teacher learning framework was designed to classify images. 2,317 images from 189 participants were included. Of these, 1,126 images revealed IRDs, 533 were normal samples, and 658 were control samples.@*RESULTS@#The FSL model achieved a total accuracy of 0.974-0.983, total sensitivity of 0.934-0.957, total specificity of 0.984-0.990, and total F1 score of 0.935-0.957, which were superior to the total accuracy of the baseline model of 0.943-0.954, total sensitivity of 0.866-0.886, total specificity of 0.962-0.971, and total F1 score of 0.859-0.885. The performance of most subclassifications also exhibited advantages. Moreover, the FSL model had a higher area under curves (AUC) of the receiver operating characteristic (ROC) curves in most subclassifications.@*CONCLUSION@#This study demonstrates the effective use of the FSL model for the classification of OCT images from patients with IRDs, normal, and control participants with a smaller volume of data. The general principle and similar network architectures can also be applied to other retinal diseases with a low prevalence.

The progress of the gene editing therapy of inherited retinal diseases based on CRISPR/Cas9 / 中华眼底病杂志

Inherited retinal diseases (IRDs) are the major cause of refractory blinding eye diseases, and gene replacement therapy has already made preliminary progress in the treatment of IRDs. For IRDs that cannot be treated by gene replacement therapy, gene editing provides an alternative therapeutic method. Strategies like disruption of pathogenic variants with or without gene augmentation therapy and precise repair of pathogenic variants can be applied for IRDs with various inheritance patterns and pathogenic variants. In animal models of retinitis pigmentosa, Usher syndrome, Leber congenital amaurosis, cone rod cell dystrophy, and other disorders, CRISPR/Cas9, base editing, and prime editing showed the potential to edit pathogenic variations in vivo, indicating a promising future for gene editing therapy of IRDs.

Reinforce revealing missing heritability in the gene of inherited retinal diseases / 中华眼底病杂志

Inherited retinal diseases (IRD) are a group of genetic disorders with high genetic and clinical heterogeneity. Genetic diagnosis has become one essential method for patients with IRD in their clinical management. So far, about 30% of the patients with IRD cannot get molecular diagnosis (no pathogenic variant detected or only mono-allele variant identified in AR genes) using target or whole exome sequencing. Most missing heritability or variants for these patients were variants located in no-coding regions (deep intron or promoter regions) and structure variants of the known IRD genes. It is more challenge to reveal this kind of missing variants, which need using whole genome sequencing combined with other cellular or molecular assays.

Characteristics of autosomal dominant retinal diseases and gene therapy strategies / 中华实验眼科杂志

Inherited retinal diseases (IRDs), one type of the major eye diseases resulting in blindness, can be caused by more than 270 identified causative genes.The most common form of IRDs is retinitis pigmentosa.There is no generally accepted cure for vision impairment due to IRDs.In recent years, the first gene replacement therapy has been approved for the treatment of autosomal recessive IRDs.Because of the variety of pathogenesis, including gain-of-function and dominant-negative effects in addition to a few loss-of-function mutations, gene replacement therapy of autosomal dominant IRDs is not always effective.The clinical manifestations of autosomal dominant IRDs are extremely complex, and there is no appropriate treatment in clinical practice.The latest progresses in pathogenesis, clinical features, treatment strategies and directions of autosomal dominant IRDs globally were reviewed, and the most common genes causing autosomal dominant IRDs were summarized in this article in order to provide a deeper understanding of autosomal dominant IRDs.

Paying attention to the natural course of disease for a development of gene therapy of inherited retinal diseases / 中华实验眼科杂志

Most inherited retinal diseases (IRDs) severely impair vision and lack effective treatments.With the approval of Luxturna, the world's first gene therapy drug for IRDs in 2017 by the U. S.FDA, gene therapy has brought new hope for the treatment of the disease.With an early onset and a relatively small number of patients, the understanding of the natural course of IRDs is limited in the past.The research on gene therapy of IRDs is mainly based on the in-depth understanding of the pathogenesis and natural course of disease, and the selection of the optimal treatment window for the implementation of gene therapy is the premise of successful treatment.At the same time, the main vector for gene therapy is recombinant virus vector, and its tissue-immunogenicity, tumorigenicity, safety of its integration with host cells and effectiveness determine the outcome of therapy, so the evaluation technology of IRDs gene therapy needs to be established.Gene therapy for ophthalmic diseases also involves the consideration of laws and regulations, ethics, product process, races and regional environment, disease progression, gene mutation types, patient benefit and risk ratio, and other factors.Therefore, it is of great significance to take full account of the differences in IRDs population, especially the particularity of children patients, and actively carry out the study on the natural course of IRDs in China for the scientific and normative development of clinical trials of gene therapy, the effective establishment of endpoint and outcome indicators for clinical studies of gene therapy, and the compliance with international norms of ethics.

Focus on the treatment of inherited retinal diseases / 中华实验眼科杂志

Inherited retinal diseases (IRDs) are rare and incurable eye diseases.Gene therapy has become a new method for the treatment of IRDs.At present, at least 26 clinical trials of gene therapy involving at least 16 different IRDs genes are in progress or imminent.Such as autosomal recessive retinitis pigmentosa (RP, MERTK mutation), choroideremia (CHM mutation), Stargardt’s disease (ABCA4 mutation), Usher syndrome 1B subtype (Myo7a mutation), X-linked retinoschisis (RS1 mutation), mitochondrial-related Leber hereditary optic neuropathy (ND4 mutation), panchromatic blindness (CNGA3 mutation and CNNGB3 mutation), sex-linked RP (RPGR mutation). Adeno-associated viral (AAV) vector-mediated gene expression is a conventional method for gene transduction, which has showed efficacies in autosomal recessive IRDs caused by small gene mutations, especially for those IRDs, which have the original lesions in retinal pigment epithelial (RPE) cells and photoreceptor cells.Novel progress has been made in animal experiments by gene editing technologies for autosomal dominant IRDs or autosomal recessive IRDs with large gene mutations, which is going to clinical trial.Oligonucleotide therapy based on RNA has also shown good efficacy for the IRDs caused by large genes, which beyond the AAV capacity.These research achievements are attacking more and more attentions in these fields.Although there are still some efficacy and safety issues on the way to treat IRDs, it is reasonable to expect that more and more patients with IRDs will be treated in the near future.

Focus on the treatment of inherited retinal diseases / 中华实验眼科杂志

Inherited retinal diseases ( IRDs) are rare and incurable eye diseases. Gene therapy has become a new method for the treatment of IRDs. At present, at least 26 clinical trials of gene therapy involving at least 16 different IRDs genes are in progress or imminent. Such as autosomal recessive retinitis pigmentosa ( RP, MERTK mutation),choroideremia (CHM mutation),Stargardt' s disease (ABCA4 mutation),Usher syndrome 1B subtype (Myo7a mutation),X-linked retinoschisis (RS1 mutation),mitochondrial-related Leber hereditary optic neuropathy ( ND4 mutation ) , panchromatic blindness ( CNGA3 mutation and CNNGB3 mutation ) , sex-linked RP ( RPGR mutation) . Adeno-associated viral ( AAV ) vector-mediated gene expression is a conventional method for gene transduction,which has showed efficacies in autosomal recessive IRDs caused by small gene mutations,especially for those IRDs,which have the original lesions in retinal pigment epithelial ( RPE) cells and photoreceptor cells. Novel progress has been made in animal experiments by gene editing technologies for autosomal dominant IRDs or autosomal recessive IRDs with large gene mutations,which is going to clinical trial. Oligonucleotide therapy based on RNA has also shown good efficacy for the IRDs caused by large genes, which beyond the AAV capacity. These research achievements are attacking more and more attentions in these fields. Although there are still some efficacy and safety issues on the way to treat IRDs,it is reasonable to expect that more and more patients with IRDs will be treated in the near future.